(This post was contributed by Reagan Templin, Lead Technical Writer for the MDS Team)

Lately, I've been seeing some confusion about creating and configuring the Master Data Manager Web application in Master Data Services (MDS) Configuration Manager. In this blog entry, I'm going to walk through the process in a bit more depth to help everyone understand more about the Web Configuration page with a focus on the Web Application area. Though I'll go over some prerequisites here, I urge everyone to read Installing and Configuring Master Data Services in SQL Server Books Online (BOL) for a workflow of the entire process of installing and configuring MDS in an environment. There are lots of good nuggets of information in that topic that I won't recover in entirety here.

Prerequisites

First, remember that Master Data Services (MDS) is 64-bit only, so whether you're evaluating MDS or beginning deployment in a dev, test, or production environment, any computers running MDS must have 64-bit hardware and run a 64-bit edition of the Windows operating system.

Speaking of operating systems, MDS requires Internet Information Services (IIS) 7.0 or later. For IIS 7.0, you need to have Windows Vista or Windows Server 2008. For IIS 7.5, you need to have Windows 7 or Windows Server 2008 R2. Additionally, the edition of IIS must have the Windows Authentication feature (if a client OS) or role service (if a server OS). The versions and editions of Windows that have Windows Authentication are listed in Setup Requirements (Master Data Services) in BOL.

Finally, you need to make sure that you've installed the necessary Windows features (if a client OS) or role services (if a server OS). These are listed in Web Application Requirements (Master Data Services) in BOL. Most of the features or role services are selected by default when you install IIS, however a couple like Windows Authentication, .NET Framework 3.0 Features, and Windows PowerShell are not default options. If you run into trouble with the Web application after you create and configure it, verify your installation options against the list in the Web Application Requirements (Master Data Services) topic and make sure you've got things configured properly. PowerShell isn't included on Windows Vista, but you can download it from the Microsoft Download Center.

Web Configuration Page: Web Application Section

Now that we've got prerequisites covered, let's get into the MDS Configuration Manager and the Web Configuration page. It's helpful to think of this page as a simplified interface for creating the MDS Web application without requiring the use of IIS Manager or other IIS tools. However, the beauty of MDS using IIS is that you can use all of the great features and functionality of IIS for your MDS Web application. So, you'll likely find MDS Configuration Manager to be a good tool for initial setup of the MDS Web application, but can then use IIS tools for more advanced configuration and full access to all the functionality IIS provides.

Most of the confusion we've seen with the Web Configuration page has to do with the Web Application section of the user interface (UI). The Web Application section is an area where you can:

Create MDS Web applications on the local computer.

Select MDS Web applications from the local computer to view or configure database and Web service options. When you select an MDS Web application, the details of the database instance and MDS database are displayed, as well as the information about whether the MDS Web application is enabled for Web services.

It's important to note that when you create a new Web site in MDS Configuration Manager, you're creating a new Web site but also creating the MDS Web application to be the root application in that site. If you aren't familiar with the changes to sites, applications, and virtual directories starting with IIS 7.0 and what all of this terminology means, read my article, Understanding Sites, Applications, and Virtual Directories, on IIS.NET that explains in further depth what is happening here.

Use the following image to decide what to do in the Web Application section. (Click the image to open a larger copy).

Important If you do not at least connect the new MDS Web application to a database, you'll run into problems when you select the site again. It will display the message that the site has no MDS Web applications, even though you created one. You must use IIS Manager or another IIS tool to delete the incomplete MDS Web application. Then add it to MDS Configuration Manager, making sure to connect it to the database this time, and click Apply. If you do not delete the incomplete MDS Web application before trying to add it again, you'll receive the error message "An unexpected error occurred: Object reference not set to an instance of an object."

Messages and Troubleshooting

Message

Description

"This Web site has no Master Data Services application. Either click Create Application to create one, or select or create another site."

You can add an MDS Web application to the selected site. If you do not want to create an MDS Web application in the selected site, select a site that you do want to create the application in or create a new site.

Create an MDS Web application in the selected site.

Select a different site from the drop-down list if you want to create the MDS Web application in a different site OR you need to select a site with an MDS Web application so that you can configure the database or Web service for that application.

Create another site if you decide that you want the MDS Web application to be in an entirely new site.

"In this tool, you can configure only one Master Data Services Web application in a Web site."

You can't have an MDS Web application nested within another MDS Web application. So, once you create a site and the root Web application is the MDS Web application, you cannot select that site and create another MDS Web application in it, otherwise you receive this message. Select a different site.